Merge remote-tracking branch 'remotes/rth/tags/pull-hppa-20190307' into staging

Fix use after free on temporary.
Optmize branch to next insn via br r0.

# gpg: Signature made Fri 08 Mar 2019 01:53:16 GMT
# gpg:                using RSA key 64DF38E8AF7E215F
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-hppa-20190307:
  target/hppa: Optimize blr r0,rn
  target/hppa: Do not return freed temporary

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>